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1.
In this study, nanocomposites of rigid poly(vinyl chloride) (UPVC) using the synthesized carbon‐coated titanium dioxide (TiO2) nanoparticles and commercial powder of titanium dioxide (with rutile structure) were prepared by melt blending. The presence of carbon‐coated TiO2 nanoparticles with rutile structure in UPVC matrix led to an improvement in photo stability of UPVC nanocomposites in comparison with commercial UPVC. The photocatalytic degradation behavior of nanocomposites was investigated by measuring their structural changes, surface tension, and mechanical and morphological properties before and after UV exposure for 700 h. It was found that mechanical and physical properties of UPVC nanocomposites are not considerably reduced after UV exposure in the presence of carbon‐coated TiO2 nanoparticles even in small percentage of nanoparticles in comparison with the presence of commercial TiO2 particles. Therefore, it can be concluded that UPVC/TiO2 nanocomposite with low content of carbon‐coated TiO2 nanoparticles(0.25 wt %) illustrated high stability under light exposure. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40228.  相似文献   

2.
Three different UV stabilizers, 2‐(2H‐benzotriazol‐2‐yl)‐4,6‐ditertpentylphenol (Tinuvin XT833), 2‐(2H‐benzotriazol‐2‐yl)‐p‐cresol (Tinuvin P), or rutile–titanium dioxide (TiO2) were incorporated into poly(vinyl chloride) (PVC) and wood/PVC (WPVC) composite, and mechanical and physical properties and photostabilities were monitored. The polyene and carbonyl sequences of PVC increased with UV weathering time and with presence of wood flour. The yellowness index increased because of polyene and carbonyl productions, whereas the brightness increased because of the photobleaching of lignin in wood. The photostabilities of PVC and WPVC could be improved through the use of UV stabilizers. Tinuvin P was recommended in this work as the most effective stabilizer for PVC and WPVC composites. The stabilization effect was interfered by presence of wood particles. The mechanical property changes corresponded well to the structural changes under UV for neat PVC. For WPVC composites, the presence of wood particles played more significant effect on the mechanical properties during UV aging than the UV stabilizer. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers  相似文献   

3.
In this study, QUV accelerated weathering of polyvinyl chloride (PVC) composites with different amounts of titanium dioxide (TiO2) particle was conducted to investigate the effect of TiO2 particle on the surface morphology and the mechanical properties. The results indicate that the surface morphology of PVC without TiO2 particle did not exhibit changes up to 960 h, but exhibited a rough and brittle surface after 1920 h of QUV accelerated weathering. In addition, the tan δ intensity, the elongation at break, and the mean failure energy (MFE) decreased significantly with increasing exposure time due to embrittlement. In contrast, for TiO2 particle‐loaded PVCs, no significant influence on the tan δ intensity and the mechanical properties after accelerated weathering were observed, despite the appreciable degradation that occurred in the surface layer. The weatherability, as determined by the mechanical performance, was improved with increasing loading of TiO2 particle in the PVC composites. Although the TiO2 particle in the PVC matrix acts as a photocatalyst to enhance the surface degradation, it is also an effective radiation screener that inhibits embrittlement and retards the decrease in mechanical properties caused by the accelerated weathering process. POLYM. COMPOS., 37:3391–3397, 2016. © 2015 Society of Plastics Engineers  相似文献   

4.
Biocomposites containing ultraviolet (UV) radiation absorbing inorganic nanofillers are of great interest in food packaging applications. The biodegradable polylactide (PLA) composite films were prepared by solvent casting method by incorporating 1 wt % of titanium dioxide (TiO2) and Ag‐TiO2 (silver nanoparticles decorated TiO2) nanoparticles to impart the photodegradable properties. The films were exposed to UV radiation for different time periods and morphology of the composite films before and after UV exposure were investigated. The results showed that homogenous filler distribution was achieved in the case of Ag‐TiO2 nanoparticles. The thermal properties and thermomechanical stability of the composite film containing Ag‐TiO2 nanoparticles were found to be much higher than those of neat PLA and PLA/TiO2 composite films. The scanning electron microscopy and X‐ray diffraction studies revealed that the photodegradability of PLA matrix was significantly improved in the presence of Ag‐TiO2 nanoparticles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

5.
A polymeric nanocomposite system (nanodielectric) was fabricated, and its mechanical properties were determined. The fabricated nanocomposite was composed of low concentrations of monodispersed titanium dioxide (TiO2) nanoparticles and an epoxy resin specially designed for cryogenic applications. The monodispersed TiO2 nanoparticles were synthesized in an aqueous solution of titanium chloride and polyethylene glycol and subsequently dispersed in a commercial‐grade epoxy resin (Araldite® 5808). Nanocomposite thin sheets were prepared at several weight fractions of TiO2. The morphology of the composites, determined by transmission electron microscopy, showed that the nanoparticles aggregated to form particle clusters. The influence of thermal processing and the effect of filler dispersion on the structure–property relationships were identified by differential scanning calorimetry and dynamic mechanical analysis at a broad range of temperatures. The effect of the aggregates on the electrical insulation properties was determined by dielectric breakdown measurements. The optical properties of the nanocomposites and their potential use as filters in the ultraviolet–visible (UV–vis) range were determined by UV–vis spectroscopy. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers  相似文献   

6.
《Ceramics International》2020,46(7):8615-8624
Titanium dioxide (TiO2) nanorods are widely used in many fields such as self-cleaning surfaces, photocatalytic lithography and pollutant control, owing to their outstanding physical, chemical and optical properties. Traditional methods for synthesizing TiO2 nanorods are mostly tedious with high cost and tremendous energy consumption. In this work, TiO2 nanorods with excellent optical, electrochemical, and hydrophilic properties were rapidly synthesized on titanium alloy (TC4) by using inductively coupled plasma (ICP) with strong chemical reactivity and high temperature characteristic. XRD patterns and SEM images confirm the conversion of TC4 into rutile TiO2 nanorods after irradiated by ICP at 800 W for only one pass, and the nanorods tend to grow longitudinally under prolonged ICP processing. Moreover, the well-developed single-crystalline feature of TiO2 nanorod is affirmed by TEM test. To reveal the growth mechanism of TiO2 nanorods, three types of substrates (polished TC4 by electrochemical polishing (ECP), polished TA2 by ECP and oxidized TC4 by anodizing) were used to grow TiO2 nanorods. However, TiO2 nanorods with good morphology were only formed on the first type of substrate due to the existence of β phase Ti, which could suppress thermal transmission between grains. In addition, the results of UV–Vis absorption spectrum, electrochemical test, and static water contact angle of the treated TC4 samples show that TiO2 nanorods synthesized by ICP possess excellent optical, electrochemical, and hydrophilic properties.  相似文献   

7.
The effects of particle size of titanium dioxide (TiO2) on mechanical, thermal, and morphological properties of pure polyoxymethylene (POM) and POM/TiO2 nanocomposites were investigated and compared with the results for nanoparticle ZnO in the same matrix, reported in a previous paper. POM/TiO2 nanocomposites with varying concentration of TiO2 were prepared by the melt mixing technique in a twin screw extruder, the same method that used for blending the homogeneous ZnO nanocomposites. The dispersion of TiO2 particles in POM nanocomposites was studied by scanning electron microscopy (SEM). The agglomeration, as observed by the mechanical properties of TiO2 particles in the polymer matrix, increased with increasing TiO2 content, a result not found for ZnO even at lower particle sizes. Increasing the filler content of POM/TD32.4 and POM/TD130 (130 nm) nanocomposites resulted in a decrease in tensile strength. The Young modulus, stress at break and impact strength of TiO2 nanocomposite did not improve with increasing filler contents, in opposition to the better agglomeration conditions of ZnO nanocomposite even at lower particle sizes. Because of agglomeration, the POM/TD32.4 nanocomposites had lower mechanical properties and lower degradation temperature than the POM/TD130 ones. The sizes of nanoparticles determined the agglomeration, but however, the agglomeration also depended on the type of nanoparticles, even when using the same matrix (POM) and the same mixing method. TiO2 nanoparticles were more difficult to mix and were more agglomerated in the POM matrix as compared to ZnO nanoparticles, regardless of the size of the nanoparticles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

8.
The polyaniline (PAn), polyaniline/titanium dioxide (PAn/TiO2), polyaniline/zinc oxide (PAn/ZnO), and a novel conducting polymer nanocomposites, polyaniline/titanium dioxide + zinc oxide (PAn/TiO2+ZnO), were synthesized by in situ electropolymerization and potential cycling on gold electrode. The PAn and nanocomposite films were characterized by cyclic voltammetry, Fourier transform infra‐red (FTIR) spectroscopy, in situ resistivity measurements, in situ UV–Visible, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The differences between cathodic and anodic peaks of three redox couples were obtained for PAn and polymeric nanocomposite films. During cathodic and anodic scans, the shift of potential was observed for polymer nanocomposite films. The characteristic FTIR peaks of PAn were found to shift to lower wavelengthsin polymer nanocomposite films. These observed effects have been attributed to interaction of TiO2, ZnO, and TiO2+ZnO particles with PAn molecular chains. Significant differences from in situ resistivity of PAn and nanocomposite films were obtained. The resistance of PAn/TiO2, PAn/ZnO, and PAn/TiO2+ZnO films were found to be smaller than the PAn film. The in situ UV–Visible spectra for Pan and polymer nanocomposite films were studied. The results show the intermediate spectroscopic properties between PAn and polymer nanocomposite films. The morphological analyses of PAn and nanocomposite films have been investigated. The nanocomposites SEM and TEM micrographs suggest that the inorganic semiconductor particles were incorporated in organic conducting polymer, which consequently modifies the morphology of the films significantly. POLYM. COMPOS., 35:351–363, 2014. © 2013 Society of Plastics Engineers  相似文献   

9.
Tieshi He  Fengmei Ren  Haihong Ma  Jin Wang 《Polymer》2009,50(13):3031-3036
The preparation and photocatalytic properties of titanium dioxide (TiO2)-fluoropolymer fiber nanocomposites were studied. The fluoropolymer nanofibers with carboxyl group were prepared by electrospinning. The complex was formed between carboxyl on fluoropolymer electrospun fiber surface and titanium ion, and then the TiO2 nanoparticles were immobilized on the surface of fluoropolymer electrospun fibers through hydrothermal complex-precipitation. By controlling the reaction conditions, different sizes and numbers of TiO2 nanocrystals can be obtained. The Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results reveal that an interaction exists between TiO2 and fluoropolymer fibers. The degradation of methylene blue solution is performed by TiO2-fluoropolymer fiber nanocomposites under UV irradiation. There may be an adsorption-migration-photodegradation process during the degradation of methylene blue by using TiO2-fluoropolymer fiber nanocomposites as photocatalyst. The experimental results show that the TiO2-fluoropolymer fiber nanocomposites have good photocatalytic ability, recycling and stability for the potential applicability in an environmental remediation.  相似文献   

10.
Conducting polyaniline (PAni)‐titanium dioxide (TiO2) nanocomposites have been synthesized by the inverted emulsion polymerization method. Aqueous mixtures of aniline, a free‐radical oxidant, and/or TiO2 nanoparticles (∼25 nm in diameter; mixture of anatase and rutile) are utilized to synthesize the hybrid nanocomposites. The polymerization is carried out in an organic solvent (chloroform, CHCl3) in the presence of a protonic acid (hydrochloric acid, HCl) as a dopant and an emulsifier (cetyl trimethylammonium bromide). The resultant PAni‐TiO2 nanocomposites are characterized with their structural, morphological, conducting, and optical properties. SEM and TEM images represent the PAni‐TiO2 nanocomposites with the diameter range of 50–200 nm. Electrical conductivities are checked by standard four‐point probes method and found to be 0.38 S/cm for bulk PAni and 0.11 S/cm for PAni‐TiO2 nanocomposites. UV–visible absorption shows two electronic bands at about 320 and 596 nm for bulk PAni and the blue‐shifted bands with the intensity changes due to the formation of PAni‐TiO2 composites. Thermogravimetric analysis reveals that the composites have a higher degradation temperature than the PAni alone. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers  相似文献   

11.
Rutile titanium dioxide (TiO2)/poly(methyl methacrylate‐acrylic acid‐butyl acrylate) nanocomposites were synthesized via seeded emulsion polymerization and characterized by Fourier transmission infrared, dynamic light scattering, X‐ray diffraction, ultraviolet–visible (UV–vis) spectroscopy, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis to study their UV‐shielding property. The effects of the nanoseed types, surfactant concentrations, and functional monomer amounts on the polymerization conversion, particle size, emulsion stability, and morphologies of the resulting nanocomposites were investigated. The dependence of UV‐shielding performance on the nanoparticle content and dispersion was also explored. The optimized results are obtained with 2 wt% of TiO2 nanoparticles addition, and the effectiveness of UV shielding is significantly increased by using the synthesized rutile nano‐TiO2/polyacrylates, for which the nanocomposite coating with a thickness of 200 μm could block up to 99.99% of UV light (≤350 nm) as confirmed by UV–vis spectrometry. POLYM. COMPOS., 36:8–16, 2015. © 2014 Society of Plastics Engineers  相似文献   

12.
In this study, the effects of the surface chemical modification of titanium dioxide (TiO2) nanoparticles and their addition into polyamide 11 (PA11) on the mechanical, dynamic‐mechanical, and tribological properties of PA11/TiO2 nanocomposites were investigated. To improve the interfacial adhesion between the nanoparticles and the polymeric matrix, the surface of TiO2 nanoparticles was modified with 3‐aminopropyl trimethoxysilane (ATPMS). Nuclear magnetic resonance (NMR), infrared spectroscopy (IR), and thermogravimetric analysis (TG) were used to evaluate the efficiency of the surface chemical modification of TiO2 nanoxide. PA11/TiO2 nanocomposites with 2 and 4 wt% of TiO2 were prepared in an internal mixer. The interfacial adhesion between the matrix and the TiO2 was evaluated by dynamic‐mechanical analysis (DMA), and the dispersion of nanoparticles was analyzed by scanning electron microscopy (SEM). The NMR spectrum of the modified TiO2 exhibited peaks in the region between −55 ppm and −70 ppm, indicating disubstituted and trisubstituted chemical structures between alkoxysilano structures and TiO2. Nanocomposites with modified TiO2 exhibited the lowest tan δ peak values, which provide evidence that the chemical modification of the TiO2 facilitated energy dissipation at the interface of TiO2 with the PA11 matrix. Surface modification of the TiO2 nanoparticles with ATPMS caused a greater reduction of the mass loss by abrasion when compared with nonmodified PA11/TiO2 nanocomposites; this reduction reached approximately 70% in comparison with the mass loss of neat PA11. POLYM. COMPOS., 37:1415–1424, 2016. © 2014 Society of Plastics Engineers  相似文献   

13.
Rutile titanium dioxide (TiO2), at different amounts (0, 1, 3, 5, 8 and 10 phr), was used to prepare PVC/TiO2 composites as cool materials. Exposure to the ultraviolet (UV)-irradiation at 65 °C (black-panel thermometers) with a xenon arc as the light source (0.51 W/(m2 nm), 340 nm) for 200, 400 and 600 h resulted in the formation of polyene structure in PVC and causing discoloration. Besides, atomic force microscopy and roughness measurements were used to examine the changes in surface topography and roughness before and after UV-irradiation. Ethylenic index was used to characterize the aging degree of composites. The contact angle value of composites became smaller and their polarity increased after exposing to UV-irradiation, but the presence of TiO2 effectively prevented this process. In addition, exposure to UV-irradiation had little effect on the reflectance of PVC/TiO2 composites over the whole solar wavelength range (200–2500 nm), especially in near infrared (NIR) region (700–2500 nm). This allowed the TiO2-loaded samples to display an excellent cooling property whether indoors or outdoors. The addition of higher quantities of TiO2 led to higher efficiency of the cooling effect. In general, this study provides strong support for the property of long-term outdoor use of PVC/TiO2 composites with high solar reflectance and excellent cooling performance.  相似文献   

14.
Nowadays, nanocomposites are a special class of materials having unique physical properties and wide application potential in diverse areas. The present research work describes an efficient method for synthesis of a series of polypyrrole/titanium dioxide (PPy/TiO2) nanocomposites with different TiO2 ratios. These nanocomposites were prepared by one‐step in situ deposition oxidative polymerization of pyrrole hydrochloride using ferric chloride (FeCl3) as an oxidant in the presence of ultra fine grade powder of anatase TiO2 nanoparticles cooled in an ice bath. The obtained nanocomposites were characterized by Fourier‐transform infrared (FTIR), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and scanning electron microscope (SEM) techniques. The obtained results showed that TiO2 nanoparticles have been encapsulated by PPy with a strong effect on the morphology of PPy/TiO2 nanocomposites. Also, the synthesized PPy/TiO2 nanocomposites had higher thermal stability than that of pure PPy. The investigation of electrical conductivity of nanocomposites by four‐point probe instrument showed that the conductivity of nanocomposite at low TiO2 content is much higher than of neat PPy, while with the increasing contents of TiO2, the conductivity decreases. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

15.
Polyurethane acrylate (PUA)–Ag/TiO2 nanocomposites were synthesized through in situ polymerization. The well-dispersed Ag/TiO2 nanorods serve as photoinitiator. Meanwhile, the PUA–Ag/TiO2 nanocomposite films exhibit superior activity toward the photocatalytic degradation of Escherichia coli under UV light. The excellent UV curing and antibacterial activities can be ascribed to the synergistic effect of Ag and TiO2, which promotes the effective electron/hole separation and thus generates various reactive species. Thin films with these nanoparticles are more hydrophilic after UV illumination. And the antibacterial mechanism of the UV-curable PUA–Ag/TiO2 nanocomposites was proposed.  相似文献   

16.
The present research work includes non-isothermal crystallization kinetics of poly(ethylene terephthalate) (PET)–titanium dioxide (TiO2) nanocomposites as well as structural and chemical properties of these nanocomposites. The average grain size of chemically synthesized TiO2 nanoparticles has been calculated 19.31 nm by TEM and XRD. The morphology and structural analysis of PET–TiO2 nanocomposites, prepared via solution casting method, has been investigated using SEM and XRD, respectively. The nature of chemical bonds has been discussed on the basis of FTIR spectra. The effect of TiO2 nanoparticles and cooling rates on non-isothermal crystallization kinetics of PET was examined by differential scanning calorimetry at various heating and cooling rates. It has been observed that TiO2 nanoparticles accelerate the heterogeneous nucleation in PET matrix. The crystallization kinetics could be explained through Avrami–Ozawa combined theory. TiO2 nanoparticles cause to make molecular chains of PET easier to crystallize and accelerate the crystallization rates during non-isothermal crystallization process; this conclusion has also been verified by Kissinger model for crystallization activation energy.  相似文献   

17.
In the present investigation, at first, the surface of titanium dioxide (TiO2) nanoparticles was modified with γ-aminopropyltriethoxy silane as a coupling agent. Then a new kind of poly(vinyl alcohol)/titanium dioxide (PVA/TiO2) nanocomposites coating with different modified TiO2 loading were prepared under ultrasonic irradiation process. Finally, these nanocomposites coating were used for fabrication of PVA/TiO2 films via solution casting method. The resulting nanocomposites were fully characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), thermogravimetric analysis/derivative thermal gravimetric (TGA/DTG), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The TEM and SEM results indicated that the surface modified nanoparticles were dispersed homogeneously in PVA matrix on nanoscale and based on obtained results a possible mechanism was proposed for ultrasonic induced nanocomposite fabrication. TGA confirmed that the heat stability of the nanocomposite was improved. UV–vis spectroscopy was employed to evaluate the absorbance and transmittance behavior of the PVA/TiO2 nanocomposite films in the wavelength range of 200–800 nm. The results showed that this type of films could be used as a coating to shield against UV light.  相似文献   

18.
Titanium oxide/graphene oxide nanocomposite thin films were grown by ultraviolet (UV) matrix‐assisted pulsed laser evaporation (MAPLE) technique in controlled oxygen or nitrogen atmospheres. The effect of graphene oxide addition and laser‐induced reduction as well as nitrogen doping on the wetting behavior and photoactive properties of titanium oxide thin films was investigated. Hydrophobic to hydrophilic conversion of titanium oxide films takes place progressively as the relative amount of graphene oxide in the MAPLE composite target increases. Nitrogen doping leads to further decrease of the static contact angle of the composite films. The photoactive properties of the synthesized materials were investigated through the evolution of contact angle under UV light irradiation. Wetting properties of both TiO2 and TiO2/GO nanocomposite thin films improved upon exposure to UV light.  相似文献   

19.
Poly(lactic acid)/titanium dioxide (TiO2) composite films were prepared by direct melt processing using three different procedures (i.e., compression molding, twin‐screw melt extrusion, and melt extrusion and thermoforming). The effect of TiO2 loading and processing procedures on the phase morphology and on the thermal, mechanical, and barrier properties of the obtained nanocomposites were analyzed respectively by field‐emission scanning electron microscopy‐energy dispersive spectrometry, differential scanning calorimetry, universal testing machine, and water vapor and oxygen permeability measurements. The incorporation of TiO2 nanoparticles into the poly(lactic acid) matrix increased the crystallinity and improved the barrier properties of the composites. The maximum tensile strength was achieved at the 2% content of TiO2 for the films produced by compression molding and twin‐screw melt extrusion, whereas the tensile strength for films produced by melt extrusion and thermoforming decreases markedly with an increasing TiO2 content. The photocatalytic activities of the obtained nanocomposites were investigated by analyzing the degradation of methyl orange. Results confirmed that the processing procedures and the distribution of TiO2 in the polymer matrix are the key parameters, which rule the photocatalytic behavior of composite films. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers  相似文献   

20.
The photostabilizing efficiency of different light stabilizers in poly(vinyl chloride) (PVC) was investigated by discoloration, ultraviolet (UV) reflection experiment, Fourier transform infrared spectrum (FTIR), and scanning electron microscopy (SEM). The results show that the addition of light stabilizers can slow down discoloration of PVC. The UV reflection results verify that this change is due to the distribution of light stabilizers on irradiated surfaces, which can absorb (such as organic stabilizers) or reflect (such as titanium dioxide) UV light differently. The order of stabilizers that can slower the extent of discoloration is titanium dioxide (TiO2) > Tinuvin 234 (U4) > XT 833 (H2), U4 > Tinuvin 531 (U3) > Chimassorb 944 (H1), phenyl salicylate (U1). FTIR results show that the carbonyl group of pure PVC, TiO2, and H1‐doped PVC increases significantly, indicating that the photo‐oxidation reactions of these irradiated samples are relatively serious. The SEM results show that the surface damages of PVC doped with U2, U4, and H2 are somehow slighter, with only small holes or cavities on the surface, whereas the surfaces of pure PVC and H1‐doped PVC are full of big and deep holes and some holes or cavities of 10 μm are detected. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers  相似文献   

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